Conventional pixel arrays are used to generate electronic images that represent a scene to which the pixel array is exposed. The conventional method of reading a pixel array is done by sequentially channeling the data from individual pixels in the pixel array. In other words, the pixels values in the pixel array are read out in a sequential manner for further processing.
In some imaging scenarios, it is unnecessary to have pixel values for every pixel in the array. As one example, in certain non-navigation related functions like finger presence detection where only a subset of pixel information is sufficient, only one or two rows of pixels statistic is used to determine whether or not a finger is present on an optical finger navigation (OFN) module. In another example using an optical mouse sensor, less than all of the pixel information from the pixel array could be used in a rest mode to sample the surface at certain intervals to check if a wakeup/transition to run mode is appropriate.
Unfortunately, many conventional imaging devices read out all pixel info in the entire array due to the limitation of the row and column decoders that work in a sequential fashion. Reading out more information than necessary can be considered wasteful in terms of power consumption and processing time. Other types of conventional imaging devices attempt to control the starting and stopping stages of which pixels will be read out. However, these conventional techniques are either inefficient or do not work well in certain situations.